Knife makers sometimes use small slabs of wood for knife
scales; These are attached to the tang of the knife with
epoxy and pins.

These knives are implanted tang-first into young trees and
are allowed to be consumed by the tree. The knife tree is
then cut down and allowed to dry. The knives
are cut out
and the handles are shaped and formed from the wood
surrounding the blanks.

This idea would work better with tools such as scythes, pickaxes and adzes where the haft passes through a hole in the blade; just hang the blade over a suitable branch and let it grow into a very tight fit.